Answers

It is Skunk cabbage as Owdboggy has said. I saw some in a stream near my house and I thought it was some sort of Peace Lily that has natrualised! As they are not hardy I looked into it and found out it's Skunk cabbage and is invasive though not known to cause problems.

I remember when Jack Drake's nursery near Aviemore was run by John Lawson the Lysichton grew all the way along the side of the burn. B & I haven't been there in years, once John sold to the new owners the nursery side went downhill - it is now known for its cakes!